Production of acetylene and olefins by partial combustion of hydrocarbons



Apnl 5, 1966 G. FAUsER 3,244,755

PRODUCTION OF ACETYLENE AND OLEFINS BY FARTIAL COMBUSTION OF HYDROCARBONS Filed 001'.. 23, 1964 United States Patent() PRODUCTION F ACETYLENE AND OLEFINS BY PARTI-AL COMBUSTIGN 0F HYDROCARBONS Giacomo Fauser, Novara,-ltaly, assigner vto Montecatini Societ Generale per IIndustria Mineraria e Chimica,

Milan, Italy l p Filed Oct. 23, 1964, Ser. No. 407,278

17 Claims. (Cl. 260'679) Y This'application is a continuation-impart of application Serial No. 757,740, filed August 28, 1958, nowabandoned, and Serial No. 860,794, tiled December Z1, 1959, now abandoned and combines both of said applications into `a single application. y

This invention relates to an improved process for'making acetylene and olelins by partial combustion of hydrocarbons with oxygen-containing gas.

In the drawings, the figure relates to vthe apparatus of application Serial No. 757,740.

T-he techniques employed hitherto comprise mixing. the hydrocanbon with oxygen, each being separately preheated, and introducing the mixture into a furnace in which `the flame is extinguished bymeans a water jet after a few hundredths olf a second. This has been practiced on a commercial scale vat a pressure very near atmospheric. Since the proportion of acetylene lin the gases thus obtained does not in practice exceed 9%, the gases are then compressed to facilitate separation of acetylene by absorption in selective solvents. However, the compression of the gas requires a marked consumption of energy. It Ialso involves technical diiiculties caused by the presence of carbon black and tars, whichY hinder-theregular operation of the apparatus.

A principal object of the present invention is`to obvi- Yate these difficulties by` carrying out the partialcombustion of hydrocanbons with oxygen under a pressure 'which is f sufficient .for the successful s-ubsequent separation of acetylene from the gases. This technique is contr-aryv to the prior belief that the chemical'equililbrium ofthe reaction resulting in acetylene would be hindered by an increase in pressure. In fact, some prior processes are carried out under vacuum. Contrary to this commonly 'held View I have found that a superatmospheric pressureof a't least two atmospheres, and especially in the range of two to six atmospheres, has very significant advantages. When t-he partial combustion of hydrocaubon (e.g.),methane with oxygen is carried out under a pressure of 3 `to 4 atm., the yield of acetylene is practically the same -as that ohq tainedunder atmospheric pressure `at a given flow-rate of the two gases.

Since the natural gas is generally available under a high pressure, its expansion down to from 3 to 4 atm. in an ejector can be used in order to compress -oxygen to .the same pressure. In the drawingsthe ejector is shown -at 6. The compression of oxygen 'hy meansof such a device also makes it possible to obtain intimate mixingof `the two gases in safest possible way, sinceif the inetihane flow Ifails', the oxygen ilow would he stopped automatically.

The gaseous mixture isintroducedrintothe comlbu'stion chamber through a distributor 7 ata rate higher than the propagation rate of the flame. The upper -part of the distributor 7 consists of a metallic plate' 70to which a number of parallel pipes 7-1 made of a special steel resistant to high temperatures are fixed. The space between the pipes is Iiilled with a refractory material 72. -A stalble flame is obtained which adheres to the lower refractory wall 73 of the distributor, which is heated to a temperature of 1400 C. This provides regular and safe operation.

vThe ameis extinguished by water spouts 9,'at a tem- .perature of' 1Z0-430 C., since ithas been -found that the carbon lblack contained in the gas is wetted only by water at ay temperature higher than 100 C. By adopting this precautioncarbon black can 4be easily separatedfrom the gas lby washing with water without iiltering.

Another Iadvantageous feature ofthe process is that the heatremoved' upon coolingtheigasescoming :from the partial combustion'rof the hydrocarbons under a pressure of 6 atm.- is used'toheat a-consi'deralble amount of water to a temperature C. This water can be advantageously employedto'regenerate' the selective solvents used to removel acetylene from the residual gases. A considerable' saving'in steamis thus obtained, in comparison with processes vin which .the partial combustion is carried out .underiatm'ospheric pressure.

A'fter the removal of carbon lblack, the gas is cooled with lwate'r, 'but it still contains aromatic hydrocarbons 'and'ftars Whichwould be absorbed in the selective solvents usefdflforiaibsorbing acetylene, thereby altering their physico-chemical properties after abrief time.

When operating under atmospheric pressure according tofpriorfproce'sses, the gases must be cooled to from 20 tok-30 C. to eliminate such hydrocarbons. In contrast, when the ygases arel available under a pressure orf from 3 to 4 atm. .a-satisffractory purification is obtained lby cooling 'to a-fternperature of y0" C., thus realizing Ia considerable s'a'vin'g'in power consumption in the cooling plant.

A preferred emlbodiment off this aspect of the invention is morespecitically described as follows:

`Methane :available under high pressure is decompressed to 16'at'm. in the pressure reducing valve 1 and, after pre- `'lic'e'a'tingtotabout 500 C. in theY heat exchanger 4, is introduced into the ejector`6.

vOxygen available Vunder a lpressure of 1 atm., after preheating to"'500 C. inthe heat exchanger 5, is sucked into the furnace 60 Iby ejector 6. lvy suitably regulating the valves "2' and 3', amixture consisting of 62% methane and 58% oxygen under a pressure of 6 atm. is thus obtained. rDhegaseous mixture passes through the pipes 7-1 of distribut-or 7, whose lower part consists of a refractory m-a- 'terial '712473, and is introduced into the combustion chamb'er S wlhere the temperature is Ibrought to 1400 C. The flame .is extinguished with water sprayed through the nozzles 9'hy the pump `10. The temperature of thecirculating water is kept at 1210 r`C. andthe separated carbon black is discharged througlhvalve 1'1'.

The gaszproduced by ypartial combustion of methane and containing y.from 8.'5 to 9% acetylene is cooled in the 4scrubber 1'3. .The Water collected on the bottom, at a vtemperatureofV 120 C., is-passed upwardly by a pump .1011toreleaseits-heatinthe heat exchanger 12 Where the yselective solventused for'the absorption of acetylene is heated. The ,gasfleaving ther tower 13 is further cooled with water-in 'thetower I5 and then, with cooling mix- Atures5-ir1 the1tower116^to0"C. to remove aromatics and tats'. Thefgasipuried from carbon black and aromatics and tars'isdinally vsubjected to a washing with selective -solvents in `order tov separate acetylene. Heat exchangers 14 and 17 are employed to preheat the replenishing water introduced ,into towers -13 and 15. The extraction of acetylene with: selective solvents'can be carried out in a "conventional gas scrubbing tower 18` similar to towers 13 to 16. The solvent is withdrawn at and passed through heat exchanger '12 and acetylene stripper 19, from which pump 181 returns it to tower 18 through cooler Note "Fauser lPatent 2,834,431. The selective solvents used are the conventional ones described in the prior fart. EPunipsll'ill-, 102, 103-recirculate the scrubbing media to 3 the tops of the towers 13, 14, 15. Valves 111, 211, 311 remove separated carbon black or aromatics.l

This aspect of the invention is in the same general field as U.S. Patent 2,894,602 of July 14, 1959, which describes acetylene, ethylene, and CO2 separation and recovery system utilized here.

The procedure usually employed in the manufacture of acetylene and olenes from liquid or gaseous hydrocarbons comprises carrying out a partial combustion with oxygen at a temperature higher than 1500 C., and then cooling the combustion products as quickly as possible, in order to prevent dissociation of the acetylene.

Such process has hitherto been operated at a pressure quite close to atmospheric, since it was thought that the equilibrium of the reaction giving rise to formation of acetylene would be hindered by pressure increase. And further, the rapid quenching was performed by extinguishing the flame by injecting water into the furnace. The entire heat of the combustion products Was effectively lost, in its removal by the cooling water.

This aspect of my invention relates to a process providing a rational utilization of the heat available in the products of partial combustion. The process entails two main features: the first consists in carrying out the incomplete combustion under an absolute pressure of from 2 to 6 atmospheres; the second consists in quenching the partial combustion products in a two stage operation: the first stage being with the aid of a hydrocarbon containing 2 or more carbon atoms, and then with Water.

I have found that when incomplete combustion of either gaseous or liquid hydrocarbons with oxygen is carried out under pressure of from 2 to 6 or preferably from 3 to 4 atmospheres, the acetylene and ethylene yields are practically as high as the yields obtained at atmospheric pressure. For example, when partial combustion is operated under a pressure of 4 atmospheres, the gas quenching permits high heat recovery in the form of hot water at a temperature as high as 130 C., which can be conveniently utilized to regenerate solvents employed in the acetylene separation from residual gases.

In addition, carrying out the partial combustion under pressure results in considerable saving of power. Ordinarily, the gases leaving the furnace must be compressed, to facilitate separation of acetylene, by the conventional Yabsorption in a solvent at a low temperature. Such cornpression is no longer necessary if as with the instant process the gases leave the furnace already under pressure.

The said two-stage quenching of the partial combustion products, carried out first with a hydrocarbon and then with water, can be employed in conjunction with any type of furnace used for producing acetylene and ethylene.

As is known, ethylene is formed at a lower thermal level than acetylene. Therefore, when, in said first stage quenching step, finely atomized liquid fuel is sprayed into the furnace through a series of holes uniformly arranged upon one or more planes normal to the furnace axis, before said water is injected, the yield of acetylene, olefines and synthesis gas is successfully increased, and to an extent substantially effecting the economic performance of the process. By this means, the output of acetylene and olenes obtained by pyrolysis, i.e. cracking, at a temperature of 1500 C. will be augmented by a further yield, obtained by taking advantage of the heat removed from the combustion products, in cooling from 1500 to 800-700 C.

In order to prevent acetylene decomposition, as soon as pyrolysis is finished the gases should be quickly quenched down to a temperature of ISO-140 C., with the aid of said water injection.

The optimum increase in production of acetylene, oleiines and synthesis gas obtained by this procedure depends upon a number of factors. For instance, it is dependent upon the properties of the hydrocarbons employed in the primary and secondary pyrolysis, on the preheating temperature, and its range. Under optimum conditions the yields of acetylene and ethylene can exceed by 50% the yields obtained by the conventional procedure, in which only water cooling is employed. This yield increase represents a real saving, since it is obtained with no further consumption of oxygen and heating fuel.

Moreover, this procedure permits variation, to a substantial extent, of the acetylene to ethylene ratio by a suitable adjustment of the hydrocarbon feed in the primary and secondary pyrolysis,

Working example The high-temperature gas obtained in a process producing acetylene by partial oxidation of methane with oxygen, was rapidly cooled down to about 750 C. by injection of gasoline (petrol) in the proportion of 130 kg. of gasoline for 1000 Nm.3 of methane. The gas mixture, constituted by the gas obtained from the thermal decomposition of the gasoline and the gas formed in the partial oxidation of methane, was rapidly cooled down to about 150 C. by means of Water. The volume of gas produced from the methane increased by about 140 Nm.3 for every kg. of gasoline introduced. The composition of the gas obtained from the thermal decomposition of the gasoline is as follows:

Nm/ 100 kg. petrol (gasoline) Other gases 367)( 103 Kcal] 100 kg. petrol.

The following computation evidences the advantage of vthe process. Suppose the following prices:

Gasoline (petrol) 20 lire/kg. Acetylene 80 lire/ kg. Ethylene 60 lire/kg. Calories in the combustible gas 2 lire/ 1000 Kcal.

Consider a plant having a potentiality of 100,000 Nm3/day of CH4; when using the instant process, the lire consumption for quenching is:

13,000 kg. of gasoline (petrol) :260,000 lire/ day while one obtains- Lire 2,900 kg. of C2H2 232,000 4,875 kg. of C2H4 292,500 11,800 Nm.3 of gases 95,000

Hence a net profit of 360,000 lire/ day is obtained, that is to say, 120,000,000 lire a year.

The gases subjected to quenching are at the pressure obtaining in the reaction zone, except for any normally small pressure losses in passing from the reaction zone to the quenching zone. The preferred quenching temperature range is about -200 C.

Application Serial No. 814,146 which was copending with the parent applications hereof is now Patent No. 3,140,323 of July 7, 1964, and describes a companion process in which the combustion gases are quenched, in one or two steps, by introducing atomized mineral oil, preferably having a boiling point above 250 C. The quenching is preferably under conditions favoring cracking, to increase the yields of acetylene and ethylene. The oil used in the first stage of the quenching lowers the temperature of the combustion gases to about 700-800 C. The oil employed in the second stage of the quenching lowers the temperature of the combustion gases to below 200 C. I claim:

1. Ina process for producing acetylene by partial combustion of methane with oxygen in a combustion zone, at a temperature and reaction duration producing acetylene, the improvement comprising separately preheating the methane and oxygen, passing the preheated methane, which is under pressure, through a restricted passage, the preheated oxygen being fed to said passage at substantially atmospheric pressure, the methane and oxygen being mixed thereby, the ow of oxygen through said passage automatically ceasing when the ow of methane fails, passing the gas mixture through a plurality of passages, in parallel arrangement, into a combustion zone, the velocity of the gas mixture in said passages being greater than the propagation Vrate of the flame in the combustion zone, the combustion zone being adjacent the exit of the ygas mixture from said plurality of passages, extinguishing said llame by means of a liquidwaterl jet the'temperature of which is above 100 C., and passing the combustion gases through a cooling and Awater scrubbing zone, and subsequently washing the gaswith a solvent for the acetylene to separate the acetylene, said partial combustion being carried out at a pressure maintained at 3 to 4 atmospheres pressure, the pressure in the ame extinguishing zone, the water scrubbing zone, and in the zone of solvent extraction of the acetylene being at a pressure greater than atmospheric,`being substantially the pressure of delivery from the preceding steps of the process.

2. The process of claim 1, including passing the scrubbing' water heated in the cooling and scrubbing Zone in indirect heat exchange with the solvent passed from the acetylene extraction step to a solvent regeneration'step in which the acetylene is stripped from the solvent.

Y 3..In a process for producing acetylene by partial combustion of a hydrocarbon gas with oxygen, at a tempera- 'ture and reaction duration producing acetylene, the improvement comprising separately preheating the oxygen and the hydrocarbon gas, the hydrocarbon gas being at a higher pressure than the oxygen, compressing the oxygen by mixing with expanding -hydrocarbon gas, the partial combustion being carried out at a pressure of at least two atmospheres and at about l400 C., the mixture of oxygen and hydrocarbon gas being fed at a velocity higher than the propagation rate of the combustion flame, extinguishing the combustion flame and separating carbon black by introducing jets of 4liquid water, the water being at a temperature above 100 C., the pressure in the flame extinguishing step being at about two to six atmospheres,

scrubbing-the gases which have`been freed of carbon black with a selective solvent to remove acetylene, saidT scrubbing being carried out at superatmospheric pressure below that at which the martial combustion is carried out.

4. In a process for producing acetylene by partial combustion of a hydrocarbon gas with oxygen, at a temperature and reaction duration producing acetylene, the improvement comprising separately preheating the oxygen and the hydrocarbon gas, the hydrocarbon gas being at a higher pressure than the oxygen, compressing the oxygen by mixing with expanding hydrocarbon gas, the partial combustion being carried out at a pressure of about 3 to 4 atmospheres, and at about 1400 C., the mixture of oxygen and hydrocarbon gas being fed through a passage at a velocity higher than the propagation rate of the combustion llame, extinguishing the combustion ame andseparating carbon black by introducing jets of liquid water adjacent the exit of the passage, the water being at a temperature above 100 C., thev pressure in the flame extinguishing step being about 3 to 4 atmospheres, scrubbing the gases which have been freed of carbon black with a selective solvent to remove acetylene, said scrubbing being carried out at superatmospheric pressure below that at which the partial combustion is carried out.

5. In a process for producing acetylene by partial combustion of hydrocarbons with oxygen, the improvement comprising carrying out the combustion at a pressure of two to six atmospheres and extinguishing the flame under said pressure by means 'of liquid Water at a temperature above C., and thereafter scrubbing and cooling the gases with water while still at superatm'ospheric pressure, the cooling being at least sufficiently low to condense the steam in the quenched gases, and subsequently removing the acetylene from the gases by a solvent for the acetylene, the heat recovered by the scrubbing and cooling step being utilized to heat the solvent to assist in removal of acetylene from it.

6. In a process for producing acetylene by partial combustion of methane with oxygen in a combustion zone, at a temperature and reaction duration producing acetylene, the improvement comprising separately preheating the methane and oxyen, passing the preheated methane, which is under pressure, through a restrictedl passage, the preheated oxygen being fed to said passage at substantially atmospheric pressure, the methane and oxygen being mixed thereby, the flow of oxygen through said passage automatically ceasing when the ilow of methane fails, passing the gas mixture through a pluralityV of passages, in parallel arrangement, into a combustion zone, the velocity of the gas mixture in said passages being greaterdthan the propagation rate of the flame in the combustion zone, the combustion zone being adjacenty the exit of the gas mixture from Asaid plurality of passages, extinguishing said ame and removing carbon blackby means of a liquid water jet the temperature of which is above 100 C., and passing the` combustion gases through a cooling and scrubbing zone in which the Water is heated to a temperature above 100 C., removing'aromatic hydrocarbons by cooling to about 0 C., and subsequently washing'the gas with solvents for the acetylene to separate Vthe acetylene, said partial combustion being carried out at 3 to 4 atmospheres pressure, the pressure in the carbon black removal and the water scrubbing zone, in the aromatic hydrocarbon removal and in the zone of solvent extraction of the acetylene being at a .pressure greater than atmospheric, being substantially the pressure of delivery fromthe preceding steps of the process.

7. In a process for producing acetylene by partial comb'ustion of hydrocarbons with oxygen, the improvement comprising carrying out the combustion at a pressure of from about two to six atmospheres and extinguishing the llame under pressure by means of liquid Water which is at a temperature above 100 C., whereby the sensible heat of the water is made available for recovery.

8. 1n a process for producing acetylene by partial combustion' of a hydrocarbon with oxygen in a combustion zone, at a temperature and reaction duration producing acetylene, the improvement comprising separately preheating the hydrocarbon and oxygen, passing the preheated gaseous hydrocarbon, which is under pressure, through` a restricted passage, the preheated oxygen being fed to said passage at a pressure of about 1 atm., the hydrocarbon and oxygen mixing in said passage, the flow of oxygen through said passage automatically ceasing when the flow of hydrocarbon fails, passing the gas mixture through a plurality of passages, in parallel arrangement, into a combustion zone, the velocity of the gas mixture in said passages being greater than the propagationrate of the llame in the combustion zone, the combustion zone being adjacent the exit of the gas mixture from said plurality of passages, extinguishing said flame and removing carbon black by means of a liquid Water jet the temperature of which is above 100 C., and passing the combustion gases through a cooling and water scrubbing zone, and thereafter washing the gas with a solvent for the acetylene to separate the acetylene, said partial combustion and flame extinction being carried out at a pressure maintained at 3 to 4 atmospheres pressure, the pressure in the water scrubbing zone and in the zone of solvent extraction of the acetylene being at a pressure greater than atmospheric, being substantially the pressure of delivery from the preceding steps of the process.

9. In a process *for producing acetylene by partial cornbustion of methane with oxygen in a combustion zone, at a temperature and reaction duration producing acetylene, the improvement comprising separately preheating the methane and oxygen, mixing the methane and oxygen, passing the gas mixture through a passage into a combustion zone, the velocity of the gas mixture in said passage being greater than the propagation rate of the ilame in the combustion zone, the combustion zone being adjacent the exit of the gas mixture from said passage, extinguishing said flame and removing carbon black by means of a liquid water jet the temperature of which is above 100 C., passing the combustion gases through a cooling and scrubbing zone, and subsequently washing the gas with a solvent for the acetylene to separate the acetylene, said partial combustion and said flame extinguishing being carried out at a pressure greater than two atmospheres and not more than six atmospheres, the pressure in the zone of solvent extraction of the acetylene being at a pressure greater than two atmospheres.

10. A method of making acetylene and ethylene, comprising subjecting a hydrocarbon to cracking by partial combustion in a reaction zone with a free-oxygen containing gas, at a temperature of at least l500 C., at a pressure of two to six atmospheres, to produce acetylene, in a second zone immediately quenching the acetylene containing gases as they leave said reaction zone at a temperature of at least 00 C., by spraying said gases with a liquid hydrocarbon in the form of droplets, with resultant production of ethylene and further production of acetylene by the cracking of said liquid hydrocarbon, the temperature being thereby decreased to 70D-800 C., and then immediately quenching the reaction gases as they leave the second zone with a spray of water to 130- 200 C., to prevent acetylene decomposition, the quenching steps also being carried out at two to six atmospheres.

11. The process of claim 10, the first hydrocarbon being natural gas, the second being gasoline.

l2. A method of making acetylene and ethylene, comprising subiecting a hydrocarbon to cracking by partial combustion in a reaction zone with a free-oxygen containing gas, at a pressure of two to six atmospheres, to produce acetylene, in a second zone immediately quenching the acetylene containing gases as they leave said reaction zone by spraying said gases with a liquid hydrocarbon in the form of droplets, with resultant production of ethylene and further production of acetylene by the cracking of said liquid hydrocarbon, and then immediately quenching the reaction gases as they leave the sec- Ond zone with a spray of water to prevent acetylene decomposition, the quenching steps also being carried out at two to six atmospheres'.

13. The process of claim 12, the quenching being carried out at a pressure of about 3 to 4 atmospheres.

14. The process of claim 12, the quenching being carried out at a pressure of about 3 atmospheres.

l5. A method of making acetylene and ethylene, comprising subjecting a hydrocarbon to cracking by partial combustion in a reaction zone with a free-oxygen containing gas, at a temperature of at least 1500" C., at a pres'- sure of two to six atmospheres, to produce acetylene, in a second zone immediately quenching the acetylene containing gases as they leave said reaction zone at a temperature of at least 1500 C., by reacting said gases with a hydrocarbon having more than two carbon atoms, with resultant production of ethylene and further production of acetylene by the cracking of the latter hydrocarbon, the temperature being thereby decreased to 700-800" C., and then immediately quenching the reaction gases as they leave the second zone with a spray of water to 200 C., to prevent acetylene decomposition, the quenching steps being carried out at above one atmosphere, being at a pressure obtaining in the said reaction zone less any pressure loss in passing from said reaction zone t0 the quenching.

16. A method of making acetylene and ethylene, comprising subjecting a hydrocarbon to cracking by partial combustion in a reaction zone with a free-oxygen containing gas, at a temperature of at least 1500 C., at a pressure of two to six atmospheres, to produce acetylene, in a second zone immediately quenching the acetylene containing gases as they leave said reaction zone at a temperature of at least l500 C., by spraying said gases with a liquid hydrocarbon in the form of droplets, with resultant production of ethylene and further production of acetylene by the cracking of said liquid hydrocarbon, the temperature being thereby decreased to 700-800" C., and then immediately quenching the reaction gases as they leave the second zone with a spray of water to 130- 200 C., to prevent acetylene decomposition, the quenching steps being carried out at above one atmosphere, being at a pressure obtaining in the saidreaction zone less any pressure loss in passing from said reaction zone to the quenching, and passing the quenched reaction gases without release of pressure to recovery process in which acetylene and olenes are separated by extraction with solvents.

17. The process of claim 16, the rst hydrocarbon being natural gas, the second being gasoline.

No references cited.

ALPHONSO D. SULLIVAN, Primary Examiner. 

1. IN A PROCESS FOR PRODUCING ACETYLENE BY PARTIAL COMBUSTION OF METHANE WITH OXYGEN IN A COMBUSTION ZONE, AT A TEMPERATURE AND REACTION DURATION PRODUCING ACETYLENE, THE IMPROVEMENT COMPRISING SEPARATELY PREHEATING THE METHANE AND OXYGEN, PASSING THE PREHEATED METHANE, WHICH IS UNDER PRESSURE, THROUGH A RESTRICTED PASSAGE, THE PREHEATED OXYGEN BEING FED TO SAID PASSAGE OF SUBSTANTIALLY ATMOSPHERIC PRESSURE, THE METHANE AND OXYGEN BEING MIXED THEREBY, THE FLOW OF OXYGEN THROUGH SAID PASSAGE AUTOMATICALLY CEASING WHEN THE FLOW OF METHANE FAILS, PASSING THE GAS MIXTURE THROUGH A PLURALITY OF PASSAGES, IN PARALLEL ARRANGEMENT, INTO A COMBUSTION ZONE, THE VELOCITY OF THE GAS MIXTURE IN SAID PASSAGES BEING GREATER THAN THE PROPAGATION RATE OF THE FLAME IN THE COMBUSTION ZONE, THE COMBUSTION ZONE BEING ADJACENT THE EXIT OF THE GAS MIXTURE FROM SAID PLURALITY OF PASSAGES, EXTINGUISHING SAID FLAME BY MEANS OF A LIQUID WATER JET THE TEMPERATURE OF WHICH IS ABOVE 100*C., AND PASSING THE COMBUSTION GASES THROUGH A COOLING AND WATER SCRUBBING ZONE, AND SUBSEQUENTLY WASHING THE GAS WITH A SOLVENT FOR THE ACETYLENE TO SEPARATE THE ACETYLENE, SAID PARTIAL COMBUSTION BEING CARRIED OUT AT A PRESSURE MAINTAINED AT 3 TO 4 ATMOSPHERES PRESSURE, THE PRESSURE IN THE FLAME EXTINGUISHING ZONE, THE WATER SCRUBBING ZONE, AND IN THE ZONE OF SOLVENT EXTRACTION OF THE ACETYLENE BEING AT A PRESSURE GREATER THAN ATMOSPHERIC, BEING SUBSTANTIALLY THE PRESSURE OF DELIVERY FROM THE PRECEDING STEPS OF THE PROCESS. 